Photonic Frequency Down-Converter based on a Frequency-Doubling OEO using Two Cascaded EAMs

Broadband Microwave Frequency Conversion Based on an Integrated Optical Micro-Comb Source

“…Although diverse functions have been demonstrated for these frequency converters, they face limitations brought about by the external electrical LO sources, which suffer from the significantly increased cost and size for multi-stage frequency multiplication and the greatly degraded spectral purity at high frequencies, thus facing huge challenges to operate at high frequencies >40 GHz. Optoelectronic oscillators can address these limitations [14,15], but are still subjected to the limited operational bandwidth caused by the electrical components (e.g., electrical amplifiers and narrow-band filters) and bulky system size involving fibre spools [16], for example.…”

“…Although diverse functions have been demonstrated for these frequency converters, they face limitations brought about by the external electrical LO sources, which suffer from the significantly increased cost and size for multi-stage frequency multiplication and the greatly degraded spectral purity at high frequencies, thus facing huge challenges to operate at high frequencies >40 GHz. Optoelectronic oscillators can address these limitations [14,15], but are still subjected to the limited operational bandwidth caused by the electrical components (e.g., electrical amplifiers and narrow-band filters) and bulky system size involving fibre spools [16], for example.Kerr optical micro-combs [17][18][19][20][21][22][23][24], particularly those in CMOS-compatible platforms [25][26][27][28][29][30], can offer many distinctive advantages to perform as an equivalent LO source for photonic microwave frequency converters. This includes the ability to generate high-frequency electrical signals ranging from 10 GHz up to 500 GHz (determined by the comb spacing), a high spectral purity enabled by the ultra-high coherence of the generated states (e.g., Turing patterns, solitons, soliton crystals etc.…”

Optically Tunable Microwave Frequency Downconversion Based on an Optoelectronic Oscillator Employing a Phase-Shifted Fiber Bragg Grating

“…The LO is generated in an OEO loop formed by a tunable laser source (TLS), two optical couplers (OC1 and OC2), a phase modulator, a PS-FBG, a photo-detector (PD1), and an electrical amplifier (EA). Different from the previously proposed OEO-based microwave downconverter schemes which have a fixed LO frequency due to the use of an electrical filter in the loop [23]- [27], this scheme employs a tunable MPF realized by a PS-FBG and a TLS to obtain a wideband tunable LO. Hence, it can achieve tunable microwave frequency downconversion in a broad frequency range.…”

Q-band oscillator at 49GHz for broadband photonic microwave frequency conversion based on a Kerr soliton crystal micro-comb

“…Although diverse functions have been demonstrated for these frequency converters, they face limitations brought about by the external electrical LO sources, which suffer from the signi cantly increased cost and size for multi-stage frequency multiplication and the greatly degraded spectral purity at high frequencies, thus facing huge challenges to operate at high frequencies >40 GHz. Optoelectronic oscillators can address these limitations [14,15], but are still subjected to the limited operational bandwidth caused by the electrical components (e.g., electrical ampli ers and narrow-band lters) and bulky system size involving bre spools [16], for example.…”